Currently, efforts to achieve a goal of zero automotive-related fatalities, meeting consumer demand and government legislation, are driving adoption of advanced automotive safety devices in the automotive industries. Automotive RADAR is one of the fast growing technologies that operate at extremely high frequency bands and supports advanced automotive safety devices. Typically, automotive RADAR supports adaptive cruise control, pre-crash protection, collision warning devices, blind spot detection, side impact detection, headway alert, automatic steering and braking intervention in an automobile. Conventionally, automotive RADAR operates in millimeter wave frequency range. The millimeter wave frequency range extends from 30 GHz to 300 GHz, as the wavelengths associated with millimeter wave frequency range are in the range of 1 to 10 millimeters.
Conventional automotive Long Range RADAR (LRR) operates in the frequency range of 76-77 GHz. Further, the analog circuits, digital components along with the radio frequency circuitry and the printed antenna design are present on the same board in the conventional automotive Long Range RADAR (LRR). Generally, in the conventional automotive Long Range RADAR (LRR), transmission of signal at millimeter wave frequency range results in very high radiation loss, dielectric loss and absorption loss. Further, at such high frequencies, is difficult to check the output of the radio frequency chip using test points or direct probing. Testing of standalone antenna to generate parameters such as Voltage Standing Wave Ratio (VSWR), gain, radiation patterns etc. also becomes inconceivable. To overcome these drawbacks, the automotive RADAR system designs are configured such that the antenna and the radio frequency chips are implemented on separate printed circuit boards (PCB).
Traditionally, the signal from one printed circuit board is connected to another printed circuit board through coaxial cable assemblies, but at millimeter wave frequencies, this methodology results in high loss. Further, 1 mm coaxial cables used for transmission of millimeter wave signals are very costly. Other conventional methodologies use standard waveguides with big flanges but such conventional methodologies enlarge the size of the overall device. The standard waveguides are also bulky and costly. Furthermore, other conventional connectors are complex and require a costly manufacturing process due to necessity of precise cavities in the PCB. Moreover, it is hard to control or measure thickness of plated copper inside the PCB cavity resulting in resonance frequency shift and thereby a lossy interconnection.